ABSTRACT: We have isolated a strain of Saprolegnia unispora whose primary zoospores exhibit a range of motilities extending from slow quivering to moderately rapid swimming depending on their sporangium of origin. Secondary spores swim normally suggesting that different subcellular mechanisms may control primary spore swimming than control that of secondary spores. A digitized video tape of this spore behavior can be viewed on the first author's web page (http://www.uncwil.edu/people/padgett). This behavior is similar to that previously reported for at least two species of Isoachlya suggesting that this genus, formerly brought into synonymy with Saprolegnia, might warrant reinstatement after further study.

KEYWORDS: Saprolegnia, Isoachlya, zoospore discharge, water mold, motility

NOMENCLATURAL NOVELTIES: None.